I was flying with a F/O the other day who said a colleague from a previous company was swimming for a while as a DEP. When he offered TRSS, a course was made available and he joined.
It might be worth ringing up and seeing just to see if they would offer a course if you were to go TRSS. You don't have to take it and can remain in the pool but it might give you an option.
I know it's frustrating as hell. I joined TRSS with a jet rating whereas people on the course before me joined from turboprops and got DEP. all depends on right place, right time.
Trouble is - is now the right time???